functions/secrets/Get-SecretAttachment.ps1

function Get-SecretAttachment {
    <#
    .SYNOPSIS
    Get a Secret attachment

    .DESCRIPTION
    Get a Secret attachment with the filename in order to write it out to disk. Combining the use of two public functions to write the attachment out to the given filename in the Secret.
    The filename of an attachment is in Get-TssSecret output (items)
    The content of the file is in Get-TssSecretField.

    .EXAMPLE
    $session = New-TssSession -SecretServer https://alpha -Credential $ssCred
    Get-TssSecretAttachment -TssSession $session -Id 35 -Slug attached-file -Path 'c:\thycotic'

    Get the Secert ID 35's field Attached File (using slug name attached-file), writing the file to c:\thycotic directory using the filename stored on that Secret

    .LINK
    https://thycotic-ps.github.io/thycotic.secretserver/commands/Get-TssSecretAttachment

    .LINK
    https://github.com/thycotic-ps/thycotic.secretserver/blob/main/src/functions/secrets/Get-SecretAttachment.ps1

    .NOTES
    Requires TssSession object returned by New-TssSession
    #>

    [CmdletBinding()]
    param (
        # TssSession object created by New-TssSession for auth
        [Parameter(Mandatory, ValueFromPipeline, Position = 0)]
        [TssSession]
        $TssSession,

        # Secret ID
        [Parameter(Mandatory, ValueFromPipelineByPropertyName)]
        [Alias('SecretId')]
        [int[]]
        $Id,

        # Field name
        [Parameter(Mandatory, ValueFromPipelineByPropertyName)]
        [Alias('FieldName')]
        [string]
        $Slug,

        # Write contents to a file (for file attachments and SSH public/private keys)
        [Parameter(Mandatory)]
        [ValidateScript( { Test-Path $_ -PathType Container })]
        [string]
        $Path,

        # Comment to provide for restricted secret (Require Comment is enabled)
        [Parameter(ParameterSetName = 'restricted')]
        [string]
        $Comment,

        # Check in the secret if it is checked out
        [Parameter(ParameterSetName = 'restricted')]
        [switch]
        $ForceCheckIn,

        # Associated ticket number (required for ticket integrations)
        [Parameter(ParameterSetName = 'restricted')]
        [string]
        $TicketNumber,

        # Associated ticket system ID (required for ticket integrations)
        [Parameter(ParameterSetName = 'restricted')]
        [int]
        $TicketSystemId
    )
    begin {
        $tssParams = $PSBoundParameters

        $restrictedParamSet = . $ParameterSetParams $PSCmdlet.MyInvocation.MyCommand.Name 'restricted'
        $restrictedParams = @()
        foreach ($r in $restrictedParamSet) {
            if ($tssParams.ContainsKey($r)) {
                $restrictedParams += $r
            }
        }
    }

    process {
        Write-Verbose "Provided command parameters: $(. $GetInvocation $PSCmdlet.MyInvocation)"
        if ($tssParams.ContainsKey('TssSession') -and $TssSession.IsValidSession()) {
            . $CheckVersion $TssSession '10.9.000000' $PSCmdlet.MyInvocation
            foreach ($secret in $Id) {
                $currentSecret = $null

                $getSecretParams = @{
                    TssSession = $TssSession
                    Id         = $secret
                }
                if ($restrictedParams.Count -gt 0) {
                    $getSecretParams.Add('Comment', $Comment)
                    $getSecretParams.Add('ForceCheckIn', $ForceCheckIn)
                    $getSecretParams.Add('TicketNumber', $TicketNumber)
                    $getSecretParams.Add('TicketSystemId', $TicketSystemId)
                }
                $currentSecret = Get-TssSecret @getSecretParams
                $currentSecretFileItem = $currentSecret.Items.Where( { $_.Slug -eq $Slug })

                if ($currentSecretFileItem.IsFile) {
                    $attachmentFilename = $currentSecretFileItem.Filename
                } else {
                    Write-Warning "Secert [$secret] and slug [$slug] is not found to be a file field"
                    continue
                }

                $fileAttachment = [IO.Path]::Combine($Path, $attachmentFilename)
                $getSecretFieldParams = @{
                    TssSession = $TssSession
                    Id         = $secret
                    Slug       = $Slug
                    OutFile    = $fileAttachment
                }
                if ($restrictedParams.Count -gt 0) {
                    $getSecretFieldParams.Add('Comment', $Comment)
                    $getSecretFieldParams.Add('ForceCheckIn', $ForceCheckIn)
                    $getSecretFieldParams.Add('TicketNumber', $TicketNumber)
                    $getSecretFieldParams.Add('TicketSystemId', $TicketSystemId)
                }
                Get-TssSecretField @getSecretFieldParams

                if (Test-Path $fileAttachment) {
                    Write-Verbose "Secret [$secret] file [$attachmentFilename] successfully written to the path [$fileAttachment]"
                    Get-ChildItem $fileAttachment
                }
            }
        } else {
            Write-Warning 'No valid session found'
        }
    }
}